Category: Equipment

database. Some of its catalogues are: the complete NGC and Messier, non stellar selections from the IC, bright stars (a selection of stars to magnitude 6.5 with historical names, Bayer and / or Flamsteed identifiers), miscellaneous variable stars, miscellaneous double stars, the planets of our solar system, and miscellaneous selections from many other deepsky catalogues.

Setup of the Argo Navis
I ordered the Argo Navis and a set of encoders (8192 steps) for the EQ 6 from JMI. The package arrived in good order, and the installation of the encoders took me about 15 minutes. The only piece of equipment I used was a screwdriver (on the images below you see the RA and DEC encoders mounted on the EQ6). After the installation of the encoders I installed 4 AA 1.5V batteries to provide the internal power for the computer (you can order an external DC power cable to connect the Argo Navis to an external power source, like a 12V car battery). Finally, I connected the computer to the encoders using the encoder cables. I was ready to do the initial setup.

RA encoder

DEC encoder

After going through the initial setup (which you only have to do once and takes about half an hour) I started the alignment procedure. This procedure has to bee done every time you setup your telescope. The alignment procedure is very simple for the EQ6. Get the scope polar-aligned as exactly as possible. Then align the telescope on a star that you select from the alignment star list in the Argo Navis, and you are ready to go.

First run of the Argo Navis
After doing the alignment I gave the Argo Navis a first try.  To locate a certain object I first had to select it from the database. After confirming the selection, the LCD display showed two coordinates. I then simply moved the telescope along both the RA and DEC axis until both coordinates were zero. If I had aligned the telescope properly, the object should be in the field of view.

The first “run” was very satisfying. From the 9 objects I selected, only 2 where a just outside my 46’ field of view. I presume that with a more accurate polar-alignment the results will be even better.

First overall impression of the Argo Navis
The JMI set of encoders and cables were very easy to install. The 178-page manual (which you will find on a CD that comes with the Argo Navis) guides you through the initial setup and the alignment procedure. The database of 29000 objects (bright stars, double stars, variables and many thousands of deep sky objects) is really impressive. You can even add more than a thousand user objects, using the software and serial cable that comes with the Argo Navis DTC. The computer provides a wealth of details for every object within the database, for example M31:

M31, also known as NGC 224, Galaxy in Andromeda,
size=3.18 degrees x 1.03 degrees, mag=3.3, SB = 14.5
morph=SA(s)b, Andromeda Galaxy M31, very bright,
RA= 00:43:00, DEC = +41deg 17’35” above horizon,
SA=4

The last data “SA=4” means that you find M31 in the SkyAtlas 2000 on map 4. You can change this into the Millennium Star Atlas or the Uranometria edition 1 chart numbers.

As you can see on the image below, the controls of the Argo Navis are very “basic”.

After you have switched the computer on you only have to operate two push buttons (exit and enter) and a big dial that lets you scroll through all the menus and catalogues. This is very convenient in the dark. The Argo Navis has an LCD-heater on board that enables you to use it in temperatures as low as -10 degrees Celsius (14 Fahrenheit). The LCD display size is 32 digits, 2 lines. You can set the scroll rate of the text and the brightness and contrast of the LCD display to your own likings.

Until now, I am very impressed by this small computer, but I will have to test it some more.  I will keep you updated about future results.

The Argo Navis on its mounting plate, attached to the EQ6

Solar PhotoFilm for visual observation without an additional neutral density eyepiece filter! That’s what the big yellow sticker on the filter says. You should use a neutral density filter ND=2, preferably one from Baader. Follow this link to find more information on the Baader AstroSolar PhotoFilm. It should be used with great care, and only by people who know the danger of observing the sun!

This filter should provide me with sharp images of the sun using much shorter exposure times (about 1/1000s). The trick is to use the Baader AstroSolar Film for visual use (ND=5) for locating the sun and focussing the image. Then mount the camera on the telescope and exchange the visual filter (ND=5) for the photographic (ND=3.8) and shoot the images. Again I must say don’t use this filter for visual use without a ND=2 greyfilter. Even if you look through the viewfinder of a normal camera, do this by holding a ND=2 filter between your eye and the camera.

I still have to test it, so I will keep you update.

For detailed instructions on how to construct a solar filter using Baader AstroSolar Filter or Baader AstroSolar Photographic filter, please follow this link!

Here are a few images that should give you an idea how I constructed the filter:

First construct a cylinder that will fit around the dewcap or the telescope
tube real tight. I used some white paper/ cardboard to do this.

Then cut two rings out of cardboard that will fit on the cardboard cylinder.

Glue the filter material between the two rings. Cut of the redundant filter material.
Your “filterholder” is ready.

Glue the filterholder onto one end of the cardboard cylinder
you made, and secure it with some extra tape.

Put the sticker with the warnings on the cylinder. This should prevent you and others
from using it visually.(I got stickers in german language, but I presume that Baader will
also have stickers in English.

images shot with a 10mm lanthanum (200x) look very promising. Here are a few pics of the mount, and the first lunar image:

a few other interesting features for astrophotography and spectroscopy.

This multi-function eyepiece comes in two parts, the eyepiece itself and a battery illuminator with adjustable brightness control. The illuminator can be attached to the eyepiece. The first thing I will have to do is to determine the exact focal length of my telescope. Only then it will be possible to use the different scales which are etched into reticle. I will keep you updated about my results!

consists of two components: the grating cell and the lens cell.

The grating cell (right), holding a blazed diffraction grating with 5600 grooves, can be screwed into the bottom of a 1.25 eyepiece. The lens cell (left), containing a lens, which magnifies the image of the spectrum, can be installed on the top of the eyepiece. With an 8-inch telescope I should be able to get some spectra from stars down to the 4th magnitude. It is also possible to photograph stellar spectra with the diffraction grating.

I didn’t have the chance to test it, but I will keep you updated!